Thursday was India's hottest day on record as the temperature reached 51 Celsius in Rajasthan. Severe heatwave conditions continue across much of the state, with Madhya Pradesh and Gujarat also experiencing the unusually high temperatures.

Much of South Asia has recorded temperatures between 3 to 5 degrees above the average. The worst of the heat has been across Pakistan and northwest India, with daytime highs around the 50C mark as the pre-monsoon heat returns to the region.

The new record was set in Phalodi in the desert state of Rajasthan with a maximum temperature of 51C on Thursday afternoon. That beats the previous record of 50.6 set 60 years earlier in the northern town of Alwar.

Churu in West Rajasthan had a high of 50.6C on Thursday. The weather was even hotter for some across the border in Pakistan. Jacobabad had a top temperature of 51.5C, while Bahawalnagar and Sibi both reach an even 50C.

May and June are the region's hottest months as temperatures climb ahead of the southwesterly monsoon. Maximum temperatures often pass 40C but 50 degrees is exceptional.

The severe heat is expected to continue through the weekend and beyond. The heat is not likely to abate significantly until the clouds roll in, bringing the summer monsoon downpours.

According to the Indian Meteorological Department, conditions are favourable for further advance of the southwest monsoon into southern parts of Bengal and the Andaman Sea during the next 48 hours. The rains are not expected across southern India before the start of June.